Interactive effect of cobalt and nitrogen on growth, nodulation, yield and protein content of field grown pea

Abstract

Pea (Pisum sativum L.) has increasing nutritional, commercial, and economical value, and initial low supply of N and Co is needed to increase nodulation, yield, and profit. A field experiment in 2010 was conducted at the University of Poonch Rawalakot located in the hilly region of the state of Azad Jammu and Kashmir, Pakistan. The aim of the study was to evaluate the effects of fertilization of N and Co on growth, nodulation, seed yield, seed composition of, and uptake of N and Co by pea plant. Treatments included three levels of N (0, 30, and 60 kg N·ha⁻¹ and represented as N₀, N₃₀, and N₆₀, respectively) combined with three levels of Co (0, 10, and 20 g Co·ha⁻¹ and represented as Co₀, Co₁₀, and Co₂₀, respectively), and the control represented as N₀Co₀. Results indicated that most of the morphological characteristics were increased with N₆₀. The greatest shoot length, root length, and chlorophyll content were recorded in the N₆₀Co₂₀. The number of root nodules increased from 6 in the control to 19 with fertilization of N and Co. Yield responses to N-Co fertilization occurred to all rates, and the highest yield, 2536 kg·ha⁻¹, was observed in the treatment N₆₀Co₁₀. Total N and Co uptake in the plant (shoot + root + seed) ranged between 16–147% and 3–331% over the control, while seed protein increased by 13–198% over the control by application of N and Co. This study demonstrates that N- and Co-deficient soils are likely to produce crops with low yields and seeds with low protein levels, and therefore, appropriate management of soil N and Co could be an effective approach to increase and sustain pea production in the small holding mountain ecosystems.